Cellulosic fiber processing

Abstract

Strengthening the dry and wet tenacity of regenerated cellulosic fibers can be performed through the addition of an aldaric acid, such as (but not limited to) glucaric acid. In some embodiments, regenerated cellulosic fibers that include an aldaric acid or a salt thereof, produced by the disclosed methods are also described. The produced fibers have advantageous properties due at least in part to the inclusion of the aldaric acid.

What is claimed is: 
     
       1. A method of processing cellulosic fiber, the method comprising:
 combining cellulosic material and aldaric acid in a first solvent to produce a first mixture including 0.1-10 weight percent aldaric acid; 
 agitating the first mixture, thereby dissolving the cellulosic material and producing a cellulosic fiber solution; 
 extruding the cellulosic fiber solution into a first bath comprising a second solvent to provide an as-spun fiber; and 
 thermally drawing the as-spun fiber through a second bath comprising oil at a temperature between 90° C. to 240° C. to produce a regenerated fiber. 
 
     
     
       2. The method according to  claim 1 , wherein the aldaric acid is glucaric acid. 
     
     
       3. The method according to  claim 1 , wherein the cellulosic material is present in the first mixture at a concentration of about 60% to about 99.9% by weight/volume. 
     
     
       4. The method according to  claim 1 , wherein the first solvent comprises sodium hydroxide, urea, N-methylmorpholine-N-oxide (NMMO) hydrate, dimethyl acetamide (DMAc), n-methylformamide (NMF), lithium chloride (LiCI), lithium bromide (LiBr), lithium fluoride (LiF), dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), 1-methyl-2-pyrrolidinone (NMP), methyl-pyrrolidones, N-Methylmorpholine-N-Oxide (NMO), diallylimidazolium methoxyacetate ([A2im][CH 3 OCH 2 COO]), pyridinium, and imidazolium or combinations thereof. 
     
     
       5. The method according to  claim 1 , wherein the first solvent comprises dimethyl acetamide (DMAc) and lithium chloride, the lithium chloride being present in the solvent at from 3% to 9% weight/volume. 
     
     
       6. The method according to  claim 1 , wherein the second solvent comprises methanol, acetone, isopropanol, water, or combinations thereof. 
     
     
       7. The method according to  claim 1 , wherein the cellulosic material is activated cellulose powder. 
     
     
       8. The method according to  claim 7 , wherein the activated cellulose powder is derived from cotton waste or agricultural waste. 
     
     
       9. The method according to  claim 1 , further comprising:
 neutralizing cellulosic material prior to combining cellulosic material with aldaric acid, and 
 adding one or more additives to the cellulosic fiber solution. 
 
     
     
       10. The method according to  claim 9 , wherein the one or more additives include water repellants, coloring agents, UV stabilizers, UV absorbers, UV blockers, antioxidants, stabilizing agents, fire retardants, and combinations thereof. 
     
     
       11. The method according to  claim 1 , further comprising aging the as-spun fiber to provide an aged as-spun fiber, where the aged as-spun fiber is subjected to drawing. 
     
     
       12. The method according to  claim 1 , further comprising generating the cellulosic material by a method including:
 milling cellulose starting material to generate a fine cellulose powder; 
 mercerizing the fine cellulose powder in aqueous sodium hydroxide; 
 neutralizing the mercerized solution with an acid; 
 rinsing and collecting fibers in the mercerized solution; and 
 drying the fibers. 
 
     
     
       13. A regenerated cellulosic fiber produced by the method of  claim 1 . 
     
     
       14. The regenerated cellulosic fiber according to  claim 13 , comprising an average fiber diameter of about 10-50 μm. 
     
     
       15. The regenerated cellulosic fiber according to  claim 13 , comprising a tenacity of 3-15 g/den. 
     
     
       16. The regenerated cellulosic fiber according to  claim 13 , comprising a specific modulus of 200-1200 g/den. 
     
     
       17. The regenerated cellulosic fiber according to  claim 13 , comprising a tensile strength of 150-2000 MPa. 
     
     
       18. The regenerated cellulosic fiber according to according to  claim 13 , comprising a linear density of 3-30 denier. 
     
     
       19. The regenerated cellulosic fiber according to  claim 13 , wherein the fiber is melt-blown, spunbond, or as-spun. 
     
     
       20. A fibrous article comprising the fiber according to  claim 13 . 
     
     
       21. The fibrous article according to  claim 20 , wherein the article is selected from the group consisting of yarn, fabric, melt-blown web, spunbonded web, as-spun web, thermobonded web, hydroentangled web, nonwoven fabric, or combinations thereof.